Difluoroamino compounds

ABSTRACT

AND R2 AND R3 ARE H OR LOWER ALKYL OF 1-4 CARBONS ATOMS, ARE USEFUL AS ENERGETIC PLASTICIZERS IN ROCKET PROPELLANTS.   -CH(-R3)-CH2-CH(-N(-F)2)-N(-F)2   WHEREIN R4 IS   R4-C(-NO2)2-CH(-R2)-CH2-CH(-N-(F)2)-N(-F)2   R2 AND R3 ARE H OR LOWER ALKYL OF 1 TO 4 CARBON ATOMS AND   -CH(-R3)-CH2-C(=N-F)-N(-F)2   WHEREIN R1 IS NO2 OR   R1-C(-NO2)2-CH(-R2)-CH2-C(=N-F)-N(-F)2   COMPOUNDS OF THE FORMULAS

United States Patent 3,714,254 DIFLUOROAMINO COMPOUNDS Clifford L. Coon, Fremont, Marion E. Hill, Palo Alto, and Donald L. Ross, Menlo Park, Calif., assignors to the United States of America as represented by the Secretary of the Navy No Drawing. Filed Sept. 24, 1970, Ser. No. 75,308 Int. Cl. C07c 87/22 US. Cl. 260-564 R 7 Claims ABSTRACT OF THE DISCLOSURE Compounds of the formulas CHCH2-(HJN F2 R and R are H or lower alkyl of 1 to 4 carbon atoms and wherein R is R3 IIIF2 JHCHr-CH-N F9 and R and R are H or lower alkyl of 1-4 carbons atoms, are useful as energetic plasticizers in rocket propellants.

BACKGROUND OF THE INVENTION This invention generally relates to organic compounds useful as plasticizers in rocket propellants and more particularly to organic compounds containing the trifluoroguanyl group and to a method of preparation thereof.

Nitrocelloluse containing rocket propellants have found extensive use in the prior art but in almost all cases it has been desirable to add a plasticizer to such propellants to improve their mechanical properties. It is desirable that these plasticizers be highly energetic and, if possible, also contribute in other ways to upgrading the propellant. There has long been a search for highly energetic plasticizers which would also increase specific impulse as Well as burning rate and simultaneously would decrease radar attenuation of rocket propellants.

SUMMARY OF THE INVENTION Accordingly one object of this invention is to provide organic compounds.

Another object of the present invention is to provide organic compounds which can be used as nitrocellulose plasticizers in rocket propellants.

A further object of this invention is to provide plasticizers for rocket propellants which increase specific impulse and burning rate.

A still further object of the instant invention is to provide plasticizers for rocket propellants which decrease radar attenuation.

A still further object of this invention is to provide a process for the preparation of these organic compounds.

Yet another object of this present invention is to provide chemical intermediates which can be used to prepare the organic compound plasticizers of this invention.

These and other objects of the invention are accomplished by providing compounds of the formula 3,714,254 Patented Jan. 30, 1973 NO: Ra NF R (i!-- HCHsi lNF:

N02 wherein R is selected from the group consisting of N0 and Rs NF R and R vary independently and are selected from the group consisting of H and lower alkyl of 1-4 carbon atoms. These compounds are prepared by a series of chemical reactions which culminate in the conversion of compounds of the formula N02 Rn NF: R. H-0Hi)H-NF,

wherein R is either N0 or R3 NF,

wherein R and R have hereinbefore been defined can be prepared by a series of chemical reactions. The compounds wherein R is N0 can be prepared by the following sequence of reactions:

6 FzNSOaH (NO:)3C H-CHzCHO Initially an il-unsaturated aldehyde of the formula R CH=CHOH0 where R is H or lower alkyl of 1-4 carbon atoms is contacted in aqueous solution with nitroform at a temperature between 0 C. and room temperature but preferably between 010 C. to yield This aldehyde is then converted to its his (difluoroamino) analogue by contacting it with difluoroamino sulfonic acid at a temperature between 0 C. and room temperature. The bis(difluoroamino) compound of the formula R1 NF: (NOz)3C-bHCH2-NF2 is converted to its trifluoroguanyl counterpart by contacting it with pyridine at a temperature between 0 and room temperature.

The compounds wherein R is are prepared by a more lengthy procedure depicted as follows:

R CH=CHzCHO (CHaCO)2O CsHsN H-N F2 is contacted in solution with KI at about room temperature to remove one of the terminal nitro groups to yield NO: R2 K(!1- HCHz-CH(OOCCH3)2 This product is then contacted with acid at about -20 C. to effect replacement of potassium with hydrogen to yield NO: R2 H- (H-CHZCH(OOCCH;)2

The product thereof is then condensed in solution with an aldehyde of the formula R CH=CH CHO at about room temperature to yield This product is then contacted in solution with acetic anhydride and acid at a temperature between 0 C., and room temperature to obtain the tetraacetoxy compound This is then converted to the corresponding tetrakis (difluoroamino) compound of the formula by contacting in solution with F NSO H at between 0 C. and room temperature. The desired amidine product of formula was obtained by contacting in solution the tetrakis (difluoroamino) compound with pyridine at a temperature between 0' C. and room temperature.

The general nature of the invention having been set forth, the following examples are presented as specific illustrations thereof. It will be understood that the invention is not limited to these specific examples but is susceptible to various modifications that will be recognized by one of ordinary skill in the art.

N,N,N trifluoro-3-methyl-4,4,4trinitrobutyramidine was prepared as follows:

EXAMPLE 1 3-methyl-4,4,4-trinitrobutyraldehyde To a cold (0-5 C.) stirred solution of 12.5 g. (0.179 mole) of crotonaldehyde in 160 ml. of water, was added dropwise over a 1.5 hour period 27 g. (0.180 mole) of nitroform in 60 ml. of water. The reaction mixture was stirred at ambient temperature for 24 hours. The aqueous phase was extracted with four 25 ml. portions of methylene chloride, and this solution was washed with three 100 ml. portions of 5% aqueous sodium bicarbonate solution followed by three 100 ml. portions of water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the methylene chloride removed at 15 mm. leaving 24.76 g. of a clear yellow oil. Purification by distillation gave a clear, colorless oil, B.P. -87 C. at 0.45 mm.; 1.4675. The structure was confirmed by IR and NMR spectra.

EXAMPLE 2 l,1-bis(difluoroamino)-3-methyl-4,4,4-trinitrobutane To a cooled (10-15 C.) stirred mixture of difluoroaminosulfonic acid (0.17 mole) in 20 ml. of sulfuric acid and 25 ml. of fluorotrichloromethane, was added dropwise 9.85 g. (0.045 mole) of 3-methyl-4,4,4-trinitrobutyraldehyde in 20 ml. of fluorotrichloromethane. The reaction mixture was stirred at ambient temperature for 15 hours. The organic phase was separated from the acid and washed with four 75 ml. portions of a 5% aqueous solution of sodium bicarbonate and four 75 ml. portions of water. The organic phase was dried with anhydrous magnesium sulfate, filtered and the fluorotrichloromethane removed at 15 mm. leaving 11.71 g. of a clear, yellow oil. The desired product was distilled at 44 C. at 0.01 mm. pressure, n 1.4367. The structure was confirmed by IR and NMR spectra.

EXAMPLE 3 N,N,N'-trifluoro-3-methyl-4,4,4-trinitrobutyramidine A solution of 4.6 g. (0.015 mole) of l,1-bis(difluoroamino)-3-methyl-4,4,4-trinitrobutane in ml. of ethylene chloride was cooled to 0-5 C. and to the stirred solution was added dropwise, over 30 minutes, a solution of 0.40 g. (0.005 mole) of pyridine in 15 ml. of methylene chloride. The reaction mixture was stirred at ambient temperature for 18 hours, then washed with two 50 ml. portions of 5% sodium bicarbonate solution and 50 ml. of Water. The organic phase was dried over magnesium sulfate, filtered, and evaporated in vacuo at 25 C. leaving 3.14 g. of a yellow oil. The oil was distilled and the desired product was collected at 60 C., 0.20 mm. pressure; 11 1.4482. IR and NMR spectra confirmed the structure.

N,N,N',N",N",N"'-hexafluoro 4,4 dinitropimelamidine is prepared by the following sequence of reactions.

5 EXAMPLE 4 Potassium 1,1-diacetoxy-4,4-dinitrobutane A solution of 5.69 g. (0.018 mole) of 1,1-diacetoxy- 4,4,4-trinitrobutane (the preparation of which is disclosed in Trinitromethane Adducts of ugh-Unsaturated Aldehydes and Acylals appearing in Journal of Chemical and Engineering Data, vol. 13, No. 3, July 1968, pages 437-9) in 34 ml. of methanol was added to a solution of 6.60 g. (0.040 mole) of potassium iodide in 90 ml. of methanol. This mixture was allowed to stir at ambient temperature for 48 hours. The iodine-colored reaction mixture was evaporated to dryness in vacuo. The black, solid mixture containing iodine and the water-soluble product was mixed with 75 ml. of water and extracted continuously with ether until the aqueous phase was free of iodine. The yellow, aqueous phase was evaporated to dryness, leaving 4.20 g. of yellow, solid product which was crystallized from hot absolute ethanol, M.P. 138 dec.

Analysis.Calcd. for C H N O K (percent): C, 31.78; H, 3.64; N, 9.27. Found (percent): C, 31.64; H, 3.53; N, 9.24.

EXAMPLE 5 1,1-diacetoxy-4,4-dinitrobutane (NO) CH-CH CH CH (OOCCHg To a stirred solution of 4.00 g. (0.013 mole) of potassium 1,1, diacetoxy 4,4 dinitrobutane in 100 ml. of water at 5 C. was added 30 ml. of 0.5 N sulfuric acid dropwise over 15 minutes while the temperature was held between 5 and 10 C. The water-insoluble product was extracted from the darkened reaction mixture with 75 ml. of methylene chloride. The organic phase was washed with a 5% sodium thiosulfate solution until it was slightly yellow, and was then washed with water. The methylene chloride solution was dried with magnesium sulfate, filtered and evaporated to give 2.25 g. of yellow oil. The product was identified by NMR and IR.

EXAMPLE 6 7,7-diacetoxy-4,4-dinitroheptanaldehyde N HOO'-'CH2'-CHZICCHZOHQOH(OOCCH3)2 To a stirred solution of 2.24 g. (0.040 mole) of acrolein in 10 ml. of water at C. was added dropwise a solution of 9.52 g. (0.035 mole) of 1,1-diacetoxy-4,4- dinitrobutane in 50 ml. of methanol. Enough methanol was added to maintain a clear solution, which was then allowed to stir at ambient temperature for 18 hours. Water (50 ml.) was added to the reaction mixture and the mixture was extracted with 75 ml. of methylene chloride. The organic phase was washed with four 25 ml. portions of water, dried over magnesium sulfate, filtered and evaporated to give 9.34 g. of a thick yellow oil which was identified by IR.

EXAMPLE 7 4,4dinitro-1,1,7,7-tetraacetoxyheptane (NO2)2C [CH2CHr-CH(OOCCHBM] 7,7-diacetoxy-4,4-dinitroheptanaldehyde, 9.34 g. (0.209 mole), was added dropwise to 45 ml. of acetic anhydride at 5 C. The mixture was held below 10 C. while 9 drops of 97% sulfuric acid was added. The reaction mixture was allowed to stir at ambient temperature for 18 hours and was then poured into 400 ml. of water at 10 C. and stirred rapidly for 45 minutes. When hydrolysis of the excess acetic anhydride was complete, the product solidified. The yellow solid was filtered, washed with water, dissolved in 200 ml. of ether and washed with five 200 ml. portions of 5% sodium bicarbonate solution. The ether phase was then washed with water, dried over magnesium sulfate and filtered. The ether was evaporated, leaving 10 g. of a light yellow solid which was recrystallized from hot hexane to give white crystals, M.P. 74-75 C.

EXAMPLE 8 4,4-dinitro-1,1,7,7-tetrakis(difluoroamino) heptane Difluoroamine (2.8 g., 0.052 mole) was condensed into a stirred mixture of 9 ml. of 30% fuming sulfuric acid (0.052 mole S0 and 20 ml. of methylene chloride at 0-5" C. To this stirred mixture was added dropwise a solution of 1.57 g. (0.004 mole) of 4,4-dinitro- 1,1,7,7-tetraacetoxyheptane in 15 ml. of methylene chloride. The reactor was sealed and the mixture was allowed to warm slowly to ambient temperature and stir for 20 hours. The reactor was flushed with nitrogen and the mixture was added dropwise with stirring to crushed ice and water. The organic phase was separated, washed several times with water, and dried over magnesium sulfate. The solvent was evaporated at 25 C., leaving 0.83 g. of product as a light yellow solid. Recrystallization of the material from a chloroform-hexane mixture gave white crystals melting at 35 C.

A solution of 0.10 g. (0.0013 mole) of pyridine in 5 ml. of methylene chloride was added dropwise to a stirred, cold (05 C.) solution of 0.61 g. (0.0015 mole) of 4,4-dinitro-l,l,7,7-tetrakis(difluoroamino) heptane in 20 ml. of methylene chloride. The mixture was allowed to stir for 2 hours at 5-l0 C. and was then washed with 20 ml. of water, 20 ml. of 5% sodium bicarbonate solution, and again with 20 ml. of water. The organic phase was dried over magnesium sulfate, filtered and evaporated in vacuo, leaving 0.46 g. of a dark oil. The oil was dissolved in chloroform and placed on a silica gel column. The desired product was eluted with a solution of 50% chloroform in hexane and detected by spraying a spot of the eluate on filter paper with TMPDA reagent. Evaporation of the solvent gave a light yellow oil which was identified by IR and NMR analysis.

Analysis.-Calcd. C H N O F (percent): C, 23.75; H, 2.27; N, 23.75. Found (percent): C, 23.62; H, 2.15; N, 23.83.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A compound of the formula wherein R is selected from the group consisting of N0 and Ra NF JH-oH2ii-NFa R is selected from the group consisting of H and lower alkyl of 1-4 carbon atoms and R is selected from the and both R and R are H.

5. Compounds of the formula wherein R is selected from the group consisting of H 20 and lower alkyl of 1-4 carbon atoms, R; is

( ]H-CHz( /H-N F2 and R is selected from the group consisting of H and lower alkyl of 1-4 carbon atoms.

6. The compounds of claim 5 wherein R is selected from the group consisting of H and CH and R is selected from the group consisting of H and CH 7. The compound of claim 6 wherein both R and R are H.

References Cited B.I.O.S. Final Report No. 709, July 1946, p. 9.

Tokin et al., Dokl. Akad. Nauk SSSR, vol. 186, N0. 1, May 1969, pp. 112 to 115.

Warner et al., J. Am. Chem. Soc., vol. 74, pp. 1064 to 1066.

LELAND A. SEBASTIAN, Primary Examiner US. Cl. X.R. 

